| 摘要 |
PURPOSE:To enable accurate detection of the edge position even when the boundary thereof is unclear, by providing a differentiater and an integrator in and edge position detecting circuit. CONSTITUTION:The imaging of an object 1 to be measured is sensed with a line sensor 2, the output of which is converted into a digital signal to be applied to a subtractor 6. The subtractor 6 outputs a signal for the object 1 being measured alone with the background signal subtracted to be memorized into a memory 9. On the other hand, difference are detected with a differentiater 15 sequentially between adjacent bits in the output of the sensor 2 while the data of the memory 9 is controlled with a CPU 13 and the differential values are integrated with an integrator 16. The differential values are integrated as intact when positive while they are integrated once a fixed value is subtracted therefrom when negative. The values thus obtained are compared with corresponding values of the memories 19 and 20 by comparators 17 and 18. The memories 19 and 20 store thresholds for decision on the edge and a CPU 13 performs a specified algorism control to detect the edge. |
